Numerous devices have been proposed to teach or correct the golf swing. Many are directed toward guiding the path of the club without controlling the movement of the player. Prior art devices which do try to control body movement are generally overly restrictive, complicated and inaccurate in the movement defined.
U.S. Pat. No. 5,156,402 issued to Hart discloses a stand which holds a handle for any athletic swinging movement with a linkage mechanism which controls movement of the handle. The machine provides resistance in order to assist as a strengthening exercise. The swing is not specifically for golf and the device does not control the position or movement of the player.
U.S. Pat. No. 4,318,546 to Chen discloses a device designed to restrict the movement of the player employing an arrangement of cross bars and straps rotationally mounted on a pivotal stand. The straps are provided to secure both the hips and shoulders of a player to the cross bars for rotation about a single axis defined by the pivotal stand. However, human mechanics do not permit the simple movement prescribed by this device. The spine does not rotate, but twists in a helix of many different axes. The hips cannot pivot about the same axis as the shoulders, and the attempt to do so would result in compensation to position and movement counter productive to the golf swing. Further, the axis for rotation of this device is not fixed, but is freely pivotal. This removes control of the motion, as the axis can change throughout the movement, and also makes it difficult for a player to use the device to return to a specific movement. Securing the player to the apparatus hinders development of the movement and supporting muscles which would occur if the player were self supported.
U.S. Pat. No. 4,758,000 issued to Cox discloses a mechanical device which provides more restriction to body movement. The player is effectively immobilized in a mechanical device which provides three pivotal linkages, to the head, the shoulders and the arms. However, the device is unsatisfactory because it is not possible to make the range of motion necessary for an effective swing. The players head is immobilized to rotation on a single axis, while the shoulders are allowed relatively free movement against a universal linkage without making any lateral movement. This produces a contorted position (seen in FIG. 4) with the head down to the side and the shoulders fully raised. The arm swing is linked by cables to the shoulder brace to force the body to twist, giving primary control to the minor muscle movement. This does not effectively guide the large body movement and requires the body to compensate for flaws caused by the swing. Again, the player is supported and moved by the apparatus, hindering development of the movement independently.
It is desired to place a players body in a correct posture for a correct swing, and to guide the body through a movement in position to make an effective swing, while preventing compensating leg movement or body tilt. It is also desired to provide a device which establishes a consistent movement to which a player may return, and against which a player may measure progress in flexibility and strength.